1. Field of the Invention
This invention relates to image projection apparatus and to lighting apparatus for use in conjunction with image projection apparatus, in particular to apparatus for projecting dynamic images.
2. Related Art
In the entertainment lighting industry, wide ranges of apparatus are known for creating lighting effects with both static and movable and controllable spotlights and there are a host of devices for altering the output of these lights; these devices include diffusers, gobos and coloured glass and plastic filters. Video and slide projectors are also increasingly used to enhance the range of techniques available to designers of entertainment, promotion, advertising and corporate presentations.
WO 98/18040 describes a light projector and associated methods of achieving various effects.
A projector based upon an array of digital micromirrors is made by Texas Instruments Inc., of Dallas, Tex., USA, and U.S. Pat. No. 5,828,485 describes uses of such a projector in obtaining gobo effects.
A further device is known from WO 98/18037 in which a beam is reflected from a mirror and an image generator is moved in tandem with movement of the mirror so as to correct for distortion caused by the movement of the mirror.
Designers at the current time seek ever to introduce further innovation in the effects they achieve through new combinations of existing equipment and faster and more accurate control of that equipment.
The present invention seeks to provide and open up a new field of light and image projection, both using static and dynamic images, and thus including video projection as well as stage and other lighting effects.
Accordingly, the present invention provides, in a first aspect, lighting apparatus, comprising:
a deflector to deflect a light beam in a plurality of directions;
image processing means to process image information, comprising an input to receive raw image information, a processor to process the raw image information into processed image information, and an output to output processed image information; and
a controller that controls operation of the processor of the image processing means according to the status of the deflector.
This apparatus is especially useful in combination with a video projector and an image source, designed for static projection of an image onto a viewing surface. In operation of one such known projector, data in an image source such as a graphics store is fed to the projector input, processed by the projector to form a projection beam and then projected. Focus and zoom controls are included on the projector as per usual. Using a personal computer (PC) an extensive range of images can be produced. The graphics store is typically in computer memory, in or adjacent the projector or remote from the projector, and used to store imagery, such as artwork, an image library, static and moving images, vector and bit map images, full-streaming video (VCR, Vcam), data output from a PC and the like. Suitable storage includes floppy disk, optical disk, DVD, mini-disk and videotape.
The present invention provides apparatus optionally in modular or kit form that modifies or updates existing video projection systems. The apparatus suitably has connections so as to intercept the data output from the graphics store, that is to say the input signal to the projector, optionally further process that data and then pass the data on to the projector. The apparatus includes a deflector which is positioned so as to deflect the light beam output from the projector. The deflector may as a side effect of deflecting the beam impart distortion to the image when its direction of projection is altered. The function of the image processor is to introduce a correction to the image data in anticipation of the distortion that occurs as a result of passing through the deflector. The function of the processor is optional in as much as the correction can be turned off or on according to the type of effect wanted. It is in addition optional to use the image processor deliberately to distort the image and/or to superimpose further and different effects upon the raw or corrected data. With knowledge of the video image desired to be seen on the viewing surface, the controller can direct appropriate processing by the processor according to the status of the deflector.
It is thus the case that the apparatus of the present invention enables a wide variety of effects to be achieved using known video projection equipment, effects not envisaged or imagined in design of the projectors. Projectors can be used dynamically to project images onto different viewing surfaces, switching from surface to surface and scanning images across surfaces whilst the apparatus continuously corrects for image distortions caused by movement of the deflector. Still and moving images can be moved like scenery without the need for heavy equipment or multiple projection systems.
The image processing means can comprise a first memory to store the raw image information and a second memory to store the processed image information. The contents of the second memory are then used for generation of the image by, for example, a projector.
In use, the deflector rotates an image in the projection beam as a consequence of deflecting the beam, and a function of the controller is to direct the processor to process the raw image information so as to provide a correction therefor in the processed image information. It is an advantage that as a result the projected video image can therefore remain upright.
It may further be necessary to correct keystoning of the image, introduced e.g. by a tilted single mirror or by the projection beam striking the screen at an angle, and a suitable correction may be achieved using a pair of prisms or a moveable lens which enable horizontal and vertical keystone to be corrected independently. Alternatively, keystoning maybe corrected by adjusting the image during or after image generation. Hence, it is further preferred that the apparatus is arranged such that when the deflector introduces a keystone effect into an image in the light beam the controller directs the processor to process the raw image information so as to provide a correction therefor in the processed image information. In apparatus that is especially preferred, there is provided the option that when the deflector both rotates an image in and introduces a keystone effect into an image in the light beam the controller directs the processor to process the raw image information so as to provide corrections for both distortions in the processed image information. In this way these two separate distortions are dealt with.
A particular apparatus of the invention also has means to correct the focus according to the direction of projection, and this correction is optionally achieved by moving an objective lens of the image projector. The correction may be calculated with reference to the distance from the image projector to the surface, and this distance may be measured using a distance detector such as an electronic range-finding device utilising the Doppler-shift effect, with a sensor mounted on the image projector. The focus correction may also be known from calibration of the equipment and pre-programmed so that when the deflectors of the apparatus are directed to deflect the beam in a given direction the distance to the viewing surface is known and the required focus adjusted according to a look-up table or similar. As will be appreciated by those in this art, the focusing means may be located in the path of the light beam between the projector and first light deflection means. Alternatively, the focusing means may be located in the path of the light beam between the first and second light deflection means. As another alternative, the focusing means may be located in the path of the light beam to focus the image deflected by the second light deflection means. The processor can thus be programmed in software so as to direct the status of the focusing means according to the status of the deflector. The controller may also direct the status of the focusing means according to the distance along the beam from the apparatus to a viewing surface. This enables dynamic changes in focus, through continuous feedback from a distance finder associated with the apparatus to the controller followed by output of an appropriate focusing signal, either to its own focusing means or to that of the projector, whilst the output of the projector is moved from one viewing surface to another. A further embodiment of the invention provides controlling inputs to a dynamic iris, preferably also by feedback to/from the controller.
Similarly, the apparatus can further comprise zoom control means, with the controller directing the status of the zoom control means according to the status of the deflector or the distance along the beam from the apparatus to a viewing surface. As with focus information, zoom signals can be output to zoom equipment of the apparatus or to external zoom equipment such as on a projector e.g. to maintain the desired image size or introduce special effects.
Preferably, the deflector has two moveable deflectors, mirrors are particularly suitable, so that the beam can be reflected in substantially any direction according to the respective positions of the mirrors. In apparatus described below in more detail, there is a first light deflection means arranged to rotate about a first axis and a second light deflection means arranged to rotate about a second axis substantially orthogonal to the first axis, and this is sometimes referred to as a double mirror head. The first and second light deflection means may also comprise first or second rotatable lenses. An advantage of a double-mirror type deflector is that the image remains orthogonal after being deflected, simplifying the correction(s) needed by the image processor e.g. to keep the image upright and free of keystone.
For ready use of the lighting apparatus with a projector, the apparatus can also include coupling means for securely coupling the lighting apparatus to a projector in such a position that the light beam output from the projector passes through the deflector of the lighting apparatus and so that the output of the image processing means of the lighting apparatus can be coupled to an input on the projector that receives image information of an image to be projected. The joining of a projector to this apparatus provides a system for light projection that greatly increases the uses and versatility of known projectors, providing a system with capabilities well beyond anything envisaged for a static projector. Inputs to the image processor and video projector are suitably in accordance with the DVI protocol.
A second aspect of the invention makes possible mechanical correction for rotation of an image by use of a double mirror head. Accordingly, apparatus of the second aspect comprises:
a deflector to defect a projection beam in a plurality of directions;
beam correction means to impart rotation of an image in the beam; and
a controller that directs the degree of rotation imparted by the beam correction means according to the status of the deflector.
Image processing means can be included, to process image information, said image processing means comprising an input to receive raw image information, a processor to process the raw image information into processed image information, and an output to output processed image information, wherein the deflector introduces a keystone effect into the image and the controller directs the image processing means to process the raw image information so as to provide a correction for that keystone effect in the processed image information. In this way, there is mechanical rotation correction and software keystone correction.
As with the apparatus of the first aspect, focusing means can be incorporated into the apparatus so the controller directs the status of the focusing means according to the status of the deflector, or the controller can comprise an output for outputting focus information to a projector, and the apparatus can include zoom control means and the controller directs the status of the zoom control means according to the status of the deflector, or the controller comprises an output for outputting zoom control information to a projector according to the status of the deflector.
A third aspect of the invention provides apparatus in which the elements described above are incorporated into one apparatus rather than by combining together various individual units. Projection apparatus of the third aspect accordingly comprises:
image processing means to process image information and comprising an input to receive raw image information, a processor to process the raw image information into processed image information, and an output to output processed image information;
a beam generator to generate a light beam from the processed image information;
a deflector to deflect the light beam in a plurality of directions; and
a controller that controls operation of the processor of the image processing means according to the status of the deflector.
Optional and preferred features of the apparatus of the first and second aspects, related to image processing, deflector(s), controller, focus control and focusing means, zoom control and zoom means, distance detection and others are similarly optional and preferred features of apparatus of the third aspects.
A fourth aspect provides light projection apparatus in which rotation correction is mechanical, and comprising:
a beam generator to generate a light beam
a beam correction means to impart rotation of an image in the beam;
a deflector to deflect the light beam in a plurality of directions; and
a controller that controls the rotation imparted by the beam correction means according to the status of the deflector.
Optional and preferred features of the apparatus of the first and second aspects, related to image processing, deflector(s), controller, focus control and focusing means, zoom control and zoom means, distance detection and others are similarly optional and preferred features of apparatus of the fourth aspects.
A fifth aspect of the invention provides a method of projecting an image in a light beam, comprising:
generating the light beam;
deflecting the light beam of a deflector, the deflector being moveable so as to deflect the beam in a plurality of directions, an effect of deflecting the beam being to rotate the beam; and
prior to deflecting the beam, imparting a rotation of the beam to correct for the rotation caused by deflecting the beam.
An effect of deflecting the beam can be to change the distance from the deflector to a surface on which the image is viewed, and the method preferably comprises adjusting the focus of the beam according to the change in distance. A further effect of deflecting the beam can be to change the distance from the deflector to a surface on which the image is viewed, wherein the method preferably comprises adjusting the zoom of the beam according to the change in distance to maintain the image size on the screen. A still further effect of deflecting the beam can be to introduce a keystone effect into an image in the beam, wherein the method preferably comprises, prior to deflecting the beam, introducing a correction to the keystone imparted by the deflecting of the beam.
References to a projector are intended to include reference to projectors that include lenses and optical elements, projection engine components the output of which may be electrical. Suitable projectors may include cathode ray tubes, light valve technology, the Texas Instruments Inc. DLP (registered trade mark) projection engine relying upon a DMD (digital micro mirror, registered trade mark) chip, liquid crystal devices such as polysilicon LCD panels (P-Si), optionally with Micro-Lens arrays or other reflective LCD devices such as JVC""s direct drive light amplifier (D-ILA).
Using the apparatus described, an image can be projected against a concave surface, such as the inside of a sphere in a specially designed viewing area with location for spectators proximal to the projector.
The apparatus can also be used to project an image onto a stage, such as a theatre stage, moving the deflector so as to move the image about the stage. One example of the invention in action comprises moving the beam so that it follows an actor as he or she moves about. A scene representing movement of an actor, say, in a car is readily achieved with projection of a static or moving background onto and around the actor; as the actor moves across the stage so the background may also follow the actor, resulting in a new and visually pleasing effect not achievable hitherto.
Another example of the invention in action comprises using apparatus to project an image onto the stage at a predetermined position, thereafter turning off the projecting means, or dimming or obscuring the output, moving the deflector and thereafter projecting an image, optionally a different one, at a second predetermined position. Use of the invention in this way reduces the need for separate lights for the separate images, or reduces the need for manual adjustments between projecting first and second images, offering a significant increase in flexibility for the operator. With the present invention it is possible to create effects that are quite different from and go far beyond presently available effects, in that dynamic video images can be projected onto and around, say, individuals on stage and tracked across the stage or across the viewing surface without distortion of the image. It is further possible to fade, rotate, shift or morph from one image to another, for example with one image superimposed on another for a part of the time between changing from one image to the nextxe2x80x94all effects not achievable using known apparatus.
The present invention aims to provide novel means for moving an image over a surface and adjusting that image according to how it is moved over the surface, allowing for rotation, keystone, focus and zoom effects. Preferably, the lighting apparatus comprises first and second rotatable light deflection means for deflecting a light beam in different directions, the beam being deflectable by the first light deflection means on to the second light deflection means so as to deflect the beam in substantially any direction. Thus, for example, a double mirror-containing head is used to direct the beam in any direction, at the control of the operator. Data feedback from the head as to the relative positions of the mirrors can be used to calculate and control the degree to which a correcting rotation and/or keystone is introduced into the image. Alternatively, the head can be instructed to direct the beam in a given direction and knowledge of that direction and the resultant correction required can be used to control the degree of correction to be made.
By providing separate image rotation means, the degree of rotation of the image can be carefully controlled, and effects as described in more detail below achieved.
In particular, the apparatus may be used to project an image contained in the light beam in many directions. An image producing device, referred to sometimes as the object, may be placed in the optical path to shape the light beam produced by the light source, or a video image may be projected. As the pan and tilt in the double mirror head are rotated, the image projected by the apparatus moves spatially. However, if the image is projected, for example, horizontally and swept about a vertical axis, without a compensating rotation of the image by the image rotation means (the processor or the beam correction means) the projected image appears to rotate about the longitudinal axis of the beam. This would be problematic when the image is asymmetrical; for example, if the projected image is a face, the face would appear to rotate with the sweeping of the light beam. The present invention thus avoids this unwanted problem.
Preferably, the apparatus further comprises control means for controlling the rate of rotation of the image by the image rotation means. The control means may be arranged to calculate a required rate of rotation of the image by the image rotation means from the rate of rotation of each of the first and second light deflection means.
In a preferred embodiment, rotation of the image in one direction by the image rotation means is adapted to compensate for rotation of the image in the other direction due to deflection thereof by the first and second light deflection means. This can enable an asymmetric image to be swept by 360 by 360 degrees (global projection) with substantially no rotation of the image about the longitudinal axis of the beam, rotation of the image due to deflection thereof by the first and second light deflection means being automatically compensated by rotation of the image rotation means.
In use of the present invention, an asymmetric image, for example a video image, is moved over a viewing surface without rotation of the image perceived by the spectator. As a spectator watches, the image remains in an upright orientation. In addition to, or as an alternative to, eliminating any rotation of the image, the image rotation means may be arranged to introduce a desired rotation of the image. This can produce spectacular optical effects; for example, the projected image can be swept through a given angle and onto different angled surfaces at different distances from the object projector with substantially no rotation thereof, and then rotated through any chosen angle whilst the mirrors in the head remain still.
To maintain an image upright as it moves across a surface, the rotation of the image rotation means needed to compensate for rotation of the image due to deflection off the deflectors may be calculated from the respective movements of the first and second light deflection means. Alternatively, using appropriate software, the compensating rotation may be obtained from a pre-calculated look-up table. Another option is to use a correction as described in WO 98/18037. One mechanical option is that the image rotation means comprises a rotatable dove prism or other mechanical device or mirror equivalent. If so, the control means may be arranged to control the rotation of the dove prism about the longitudinal axis of the light beam.
The apparatus may further comprise beam generating means for generating the light beam and beam shaping means for altering the shape of the light beam to generate the image in the light beam. The beam shaping means may comprise a selective light reflecting or transmitting device. This can enable the shape of the image to be dynamically controlled. The light reflecting device can comprise a plurality of digitally controllable micromirrors, P-Si with a micro-lens array, D-ILA or any other suitable image delivery system.
The present invention also provides a method of projecting an image in a light beam by deflecting the beam using first light deflection means on to second light deflection means, and rotating both light deflection means so as to deflect the beam substantially in any direction, the method comprising the step of rotating the image in the light beam using image rotation means.
Preferably, the method further comprises the step of controlling the rate of rotation of the image by the image rotation means. The rate of rotation of the image by the image rotation means may be calculated from the rate of rotation of each of the first and second light deflection means.
Preferably, rotation of the image due to the deflection thereof by the first and second light deflection means is compensated by the rotation of the image by the image rotation means. In one preferred embodiment, the image rotation means comprises a rotatable dove prism.
A further aspect of the invention provides video image recording apparatus, comprising
a video image recorder;
first and second rotatable light deflection means for deflecting light in different directions, the light being deflectable by the first light deflection means on to the second light deflection means; and
image rotation means for rotating an image in the light;
wherein the first and second light deflection means can be so moved as to deflect light from substantially any direction through the image rotation means and into the video image recorder.
This confers the advantage that the video image recorder can be statically mounted but nevertheless used to record a video image emanating from substantially any direction. The recorder is preferably a video camera.
In a specific embodiment of the invention, the video camera is a security camera. The invention thus enables the security camera to be securely mounted whilst movement of the image rotation means and the light deflection means enable pictures from substantially any direction to be recorded. The camera itself can for example be mounted inside or behind a wall, and thus made more remote from and more secure from tamper. Using the image rotation means, whether electrical or mechanical, to compensate for rotation of the image due to deflection off the deflection means has the result that an upright image can be recorded whatever its origin relative to the stationary camera.
It is further preferred that the recording apparatus includes focusing and zoom control means according to the first and second aspects of the invention, to enable adjustment of focus and zoom according to the distance from the apparatus to the subject being recorded. In conjunction with focus and, or zoom control a distance detector can be provided for dynamic adjustment of these parameters.